Temperature-insensitive large electro strains and electric field induced intermediate phases in (0.7-x)Bi(Mg1/2Ti1/2)O3-xPb(Mg1/3Nb2/3)O3-0.3PbTiO3 ceramics

Large electrostrains (similar to 0.4% at 7 kV/mm) of the new (0.7 - x)Bi(Mg1/2Ti1/2)O-3-xPb(Mg1/3Nb2/3)O-3-0.3PbTiO(3) ((0.7 - x)BMT-xPMN-0.3PT) ceramics with x = 0.0-0.7 near the morphotropic phase boundary of the BMT-PT-PMN ternary system were found to be associated with the evolution of the compositionally modulated dielectric relaxor behavior. As disclosed by in situ high-resolution synchrotron X-ray diffraction, more intermediate phases of different symmetries induced by external fields largely contribute to smaller strain hysteresis (similar to 23%) of PMN-rich compositions than BMT-rich ones. Particularly, the x = 0.2 sample exhibits temperature-insensitive electrostrains of similar to 0.3% at 5 kV/mm varying less than 10% from room temperature up to 160 degrees C, which is mainly attributed to the coexistence of two kinds of relaxer states in a broad temperature range owing to special static domain structures typical for BMT-rich compositions. These findings provide a new approach toward an appropriate compositional design for low-hysteresis temperature-insensitive large electrostrains in BMT-based relaxor ferroelectrics. (C) 2014 Elsevier Ltd. All rights reserved.